The effects of humoral agents on the myoelectrical activity of the terminal ileum

Waterfall, W. E.; Brown, Bethany H.; Duthie, H. L.; Whittaker, G. E.

doi:10.1136/gut.13.7.528

Cited by 23 publications

(6 citation statements)

References 16 publications

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“…In his classic review, Davenport (14) cited Roman and colleagues, who demonstrated in the human duodenum, slow waves at a frequency of 11.2-12.6/min with superimposed action potentials (37). Slow waves in the human ileum were measured at 6.5-9.3/min (50). Several studies (8,21,47) reported that slow-wave frequency decreased from 11/min in the duodenum to 6/min in the human ileum.…”

Section: Myogenic Activitymentioning

confidence: 99%

Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum

Kuizenga

Sia

Dodds

et al. 2015

American Journal of Physiology-Gastrointestinal and Liver Physi

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Kuizenga MH, Sia TC, Dodds KN, Wiklendt L, Arkwright JW, Thomas A, Brookes SJ, Spencer NJ, Wattchow DA, Dinning PG, Costa M. Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum. Am J Physiol Gastrointest Liver Physiol 308: G1-G11, 2015. First published November 13, 2014; doi:10.1152/ajpgi.00230.2014.-Narrow muscle strips have been extensively used to study intestinal contractility. Larger specimens from laboratory animals have provided detailed understanding of mechanisms that underlie patterned intestinal motility. Despite progress in animal tissue, investigations of motor patterns in large, intact specimens of human gut ex vivo have been sparse. In this study, we tested whether neurally dependent motor patterns could be detected in isolated specimens of intact human ileum. Specimens (n ϭ 14; 7-30 cm long) of terminal ileum were obtained with prior informed consent from patients undergoing colonic surgery for removal of carcinomas. Preparations were set up in an organ bath with an array of force transducers, a fiberoptic manometry catheter, and a video camera. Spontaneous and distension-evoked motor activity was recorded, and the effects of lidocaine, which inhibits neural activity, were studied. Myogenic contractions (ripples) occurred in all preparations (6.17 Ϯ 0.36/min). They were of low amplitude and formed complex patterns by colliding and propagating in both directions along the specimen at anterograde velocities of 4.1 Ϯ 0.3 mm/s and retrogradely at 4.9 Ϯ 0.6 mm/s. In five specimens, larger amplitude clusters of contractions were seen (discrete clustered contractions), which propagated aborally at 1.05 Ϯ 0.13 mm/s and orally at 1.07 Ϯ 0.09 mm/s. These consisted of two to eight phasic contractions that aligned with ripples. These motor patterns were abolished by addition of lidocaine (0.3 mM). The ripples continued unchanged in the presence of this neural blocking agent. These results demonstrate that both myogenic and neurogenic motor patterns can be studied in isolated specimens of human small intestine. small intestine; motor patterns; enteric nervous system; myogenic; neurogenic PROPULSION AND MIXING OF INTESTINAL CONTENTS along the digestive tract are essential for normal digestion. The motor patterns underlying these functions are due to the coordinated contractions and relaxations of the smooth muscle layers of the intestine. The internal circular smooth muscle layer and the external longitudinal smooth muscle layer are controlled by two main mechanisms. Myogenic activity is driven by the nonneural pacemaker cells, the interstitial cells of Cajal. Neurogenic control is mediated by circuits in the enteric nervous system. These two types of activity combine to generate the motor patterns that mix and propel luminal content (14,29). Most of our understanding of these mechanisms has been derived from animal studies. Although the basic functions of the gastrointestinal tract are similar between human and animals, there are si...

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Section: Myogenic Activitymentioning

confidence: 99%

Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum

Kuizenga

Sia

Dodds

et al. 2015

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…Radioimmunologic measurements of secretin and CCK indi cate that the active plasma concentrations of these hormones might be low (3,4,16). But, when lower doses than 0.5 U/kg/h of secretin were tested in man (27) or such low doses of CCK in animal experiments (18,24), these small amounts of the hormones were also active on the small intestine. These observations suggest that secretin and CCK are involved in the intricate mechanism modu lating the motor function of the gut.…”

Section: Discussionmentioning

confidence: 99%

Effects of Secretin and Cholecystokinin on Motor Activity of Human Jejunum

Dollinger¹,

Berz²,

Raptis³

et al. 1975

Digestion

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The effects of intravenous administration of secretin and cholecystokinin (CCK) on motility of the human jejunum were investigated with pressure-sensitive radiotelemetering capsules. Secretin inhibited and CCK stimulated the spontaneous motor activity of this part of the small intestine. Raising the dosages of the two hormones caused increasing effects. It seems likely, therefore, that both hormones play a role in the regulation of intestinal motility in man.

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“…Some workers have reported that pen-tagastrin results in a dose-dependent increase in the frequency of duodenal pacesetter potentials [44], while others have found that gastrin and pentagastrin cause no change in the frequency of the pacesetter potentials of the duodenum [45,46], jejunum [46], or ileum [47]. In contrast, most workers have confirmed Gregory and Tracy's early finding that gastrin stimulates contractions in the small intestine [27,[45][46][47][48][49]. Gregory and Tracy [27] showed that an intravenous bolus of gastrin causes rapid phasic contractions in the jejunum, after which a prolonged period of decreased tone occurs [27].…”

Section: Small Intestinementioning

confidence: 99%

“…Gregory and Tracy [27] showed that an intravenous bolus of gastrin causes rapid phasic contractions in the jejunum, after which a prolonged period of decreased tone occurs [27]. The stimulation of contractions is triggered by a gastrin-induced increase in small intestinal action potentials [45][46][47]. The influence of gastrin on intestinal transit has not been studied.…”

Section: Small Intestinementioning

confidence: 99%

“…In contrast to gastrin, CCK, motilin, and VIP, secretin reduces the incidence of action potentials and contractions in the small bowel without significantly affecting the frequency or velocity of the small intestinal pacesetter potentials [45,47,64,65]. The inhibition of action potentials is greater in the duodenum and jejunum than in the ileum [64], and both Type I and Type III contractions are inhibited [45,47,53,54]. Secretin also inhibits CCK-induced contractions as well as spontaneous contractions, although the secretin-induced inhibition can be overcome by large doses of CCK [51].…”

Section: Small Intestinementioning

confidence: 99%

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Hormonal control of gastrointestinal motility

1979

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The objective of these studies was to assess the role of gastrointestinal hormones in controlling gastrointestinal motility. In the proximal stomach, cholecystokinin (CCK), gastrin, and secretin inhibit contractions, thereby decreasing intragastric pressure and slowing gastric emptying of liquids. Gastric inhibitory polypeptide (GIP), glucagon, and vasoactive intestinal peptide (VIP) may also slow gastric emptying, since they also inhibit proximal gastric contractions, but this was not tested. In contrast, motilin augments proximal gastric contractions and speeds gastric emptying of liquids. The contractions of the distal stomach are stimulated by gastrin, CCK, and motilin and inhibited by secretin, gastric inhibitory polypeptide, and VIP. The modulation of distal gastric contractions by these hormones may influence gastric trituration and emptying of solids, but this is unknown. Pyloric contractions are enhanced by CCK and secretin, an effect blocked by gastrin. Such enhancement ought to decrease duodenal‐gastric reflux, but again, this is untested. In the small bowel, CCK, gastrin, motilin, VIP, and glucagon stimulate contractions, while secretin inhibits contractions. CCK and motilin speed small bowel transit, but VIP and glucagon slow transit. The cyclical bursts of gastroduodenal contractions that occur during fasting are associated with increased concentrations of motilin in the plasma, whereas the contractions characteristic of the fed state are copied by exogenous administration of gastrin and CCK. Of all these actions, only those of CCK on the proximal stomach, and gastrin on the distal stomach, have been shown to be physiologic so far.

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The effects of humoral agents on the myoelectrical activity of the terminal ileum

Cited by 23 publications

References 16 publications

Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum

Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum

Effects of Secretin and Cholecystokinin on Motor Activity of Human Jejunum

Hormonal control of gastrointestinal motility

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